barnacle

¹ American  

[bahr-nuh-kuhl] / ˈbɑr nə kəl /

noun

1. any marine crustacean of the subclass Cirripedia, usually having a calcareous shell, being either stalked goose barnacle and attaching itself to ship bottoms and floating timber, or stalkless rock barnacle, or acorn barnacle and attaching itself to rocks, especially in the intertidal zone.

2. a person or thing that clings tenaciously.

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barnacle ² American  

[bahr-nuh-kuhl] / ˈbɑr nə kəl /

noun

1. Usually barnacles. an instrument with two hinged branches for pinching the nose of an unruly horse.

2. British Dialect. barnacles, spectacles.

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barnacle British  

/ ˈbɑːnəkəl /

noun

1. any of various marine crustaceans of the subclass Cirripedia that, as adults, live attached to rocks, ship bottoms, etc. They have feathery food-catching cirri protruding from a hard shell See acorn barnacle goose barnacle

2. a person or thing that is difficult to get rid of

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barnacle Scientific  

/ bär′nə-kəl /

1. Any of various small marine crustaceans of the subclass Cirripedia that form a hard shell in the adult stage and attach themselves to underwater surfaces, such as rocks, the bottoms of ships, and the skin of whales.

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Other Word Forms

• barnacled adjective

Etymology

Origin of barnacle¹

First recorded in 1580–85; perhaps a conflation of barnacle “barnacle goose” with Cornish brennyk, Irish báirneach “limpet,” Welsh brenig “limpets,” reflecting the folk belief that such geese, whose breeding grounds were unknown, were engendered from rotten ships' planking; barnacle goose

Origin of barnacle²

1350–1400; Middle English bernacle bit, diminutive of bernac < Old French < ?

Explanation

A barnacle is a spineless animal that looks like a small circular white rock. You'll often find barnacles attached to the bottom of boats. Barnacles are crustaceans, which means they're related to crabs, lobsters, and shrimp, all of which have an external shell. In the case of barnacles, their shells attach to things like rocks, other shells, docks, and boats, and stay there permanently, filtering food from shallow ocean water through feathery appendages. The earliest use of the word referred to a European goose whose mythology described it hatching from the marine crustacean that eventually took its name.

Example Sentences

A Ram truck with a yellow barnacle on its windshield, a handful of mopeds under rain covers, and a lot of empty parking spaces.

From Slate • Apr. 28, 2025

In the UK, rising sea temperatures are having an impact, with a number of creatures having vanished completely from coastal locations - some barnacle species, for example.

From BBC • May 7, 2024

The team also used published research and field surveys to find out how barnacle populations overlap with the range expansion of warm-water predatory sea snails.

From Science Daily • Nov. 9, 2023

“We are quite poor at remembering how things were 20, 30 years ago, unless we have some notes,” he says, as barnacle geese bark in flight above him.

From Science Magazine • Sep. 26, 2023

And he kept discovering new species of barnacle.

From "Charles and Emma: The Darwins' Leap of Faith" by Deborah Heiligman